Semiconductor device with discrete blocks

ABSTRACT

A semiconductor device and a method of manufacture are provided. In particular, a semiconductor device using blocks, e.g., discrete connection blocks, having through vias and/or integrated passive devices formed therein are provided. Embodiments such as those disclosed herein may be utilized in PoP applications. In an embodiment, the semiconductor device includes a die and a connection block encased in a molding compound. Interconnection layers may be formed on surfaces of the die, the connection block and the molding compound. One or more dies and/or packages may be attached to the interconnection layers.

PRIORITY CLAIM

This application is a divisional of U.S. patent application Ser. No.14/886,775, entitled “Semiconductor Device with Discrete Blocks,” filedon Oct. 19, 2015 which application is a divisional of U.S. patentapplication Ser. No. 13/608,946, entitled “Semiconductor Device withDiscrete Blocks,” filed on Sep. 10, 2012, now U.S. Pat. No. 9,165,887issued on Oct. 20, 2015, which applications are incorporated herein byreference.

BACKGROUND

Since the invention of integrated circuits, the semiconductor industryhas experienced continuous rapid growth due to constant improvements inthe integration density of various electronic components (i.e.,transistors, diodes, resistors, capacitors, etc.). For the most part,this improvement in integration density has come from repeatedreductions in the minimum feature size, allowing more components to beintegrated into a given chip area. These integration improvements areessentially two-dimensional (2D) in nature, in that the volume occupiedby the integrated components is essentially on the surface of thesemiconductor wafer. Although dramatic improvements in lithography haveresulted in considerable improvements in 2D integrated circuitformation, there are physical limitations to the density that can beachieved in two dimensions. One of these limitations is the minimum sizeneeded to make these components. Also, when more devices are put intoone chip, more complex designs are required.

One packaging technique that has been developed is Package-on-Package(PoP). As the name implies, PoP is a semiconductor packaging innovationthat involves stacking one package on top of another package. Forexample, a PoP device may combine vertically discrete memory and logicball grid array (BGA) packages. In PoP package designs, the top packagemay be interconnected to the bottom package through peripheral solderballs, wire bonding, or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present embodiments, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIGS. 1a-1c depict cross-sectional and plan views of an embodiment;

FIGS. 2a-2c depict an enlarged cross-sectional view of a block inaccordance with embodiments;

FIG. 3 depicts a cross-sectional view of an embodiment involving a PoPdevice; and

FIGS. 4a-4j depict a process flow for the construction of an embodiment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of embodiments are discussed in detail below. Itshould be appreciated, however, that the present disclosure providesmany applicable inventive concepts that can be embodied in a widevariety of specific contexts. The specific embodiments discussed aremerely illustrative of specific ways to make and use the disclosedsubject matter, and do not limit the scope of the different embodiments.

Embodiments will be described with respect to a specific context, namelya Package-on-Package (PoP) structure with integrated passive devices(IPDs). Specific embodiments will highlight the use of discrete blocks,such as discrete silicon or SiO₂ blocks, encased within a moldingcompound. The discrete blocks may be used to form IPDs, through vias(TVs) (e.g., through-silicon vias (TSVs), and/or the like, to provideelectrical connections in PoP applications. Other embodiments may beused in other applications, such as with interposers, packagingsubstrates, or the like.

FIG. 1a depicts a cross-sectional view of a first package 10 inaccordance with an embodiment. The first package 10 comprises a firstinterconnect layer 11 having one or more dies (one die 12 being shown)coupled thereto. The first interconnect layer 11 may comprise one ormore layers of dielectric material 16 with conductive features(illustrated as conductive features 15) formed therein. In anembodiment, the layers of dielectric material 16 are formed of aphoto-sensitive material such as polybenzoxazole (PBO), polyimide (PI),benzocyclobutene (BCB), or the like, which may be easily patterned usinga lithography mask similar to a photo resist. In alternativeembodiments, the layers of dielectric material 16 may be formed of anitride such as silicon nitride, an oxide such as silicon oxide,phosphosilicate glass (PSG), borosilicate glass (BSG), boron-dopedphosphosilicate glass (BPSG), or the like. In an alternative embodimentthe first interconnect layer 11 may comprise an interposer or packagingsubstrate, such as a silicon interposer, organic substrate, a laminatesubstrate (e.g., a 1-2-1 laminate substrate), or the like. Asillustrated in FIG. 1a , the first interconnect layer 11 provideselectrical connections between opposing sides and may act as aredistribution layer (RDL). A first set of external contact pads 17provide an external electrical connection using, for example, solderballs 19.

The die 12 is laterally encased in a material layer, such as a moldingcompound 14, which may have one or more connection blocks 20 positionedtherein. As illustrated in FIG. 1a , the connections blocks 20 arealigned along a major axis of the die 12, and the molding compound 14 isinterposed between the die 12 and the connection blocks 20. Theconnection blocks 20 may include, for example, through vias (TVs) and/orintegrated passive devices (IPDs). Generally, as described in greaterdetail below, the connection blocks 20 provide a structural materialthat allows a higher density of structures, such as TVs and/or IPDs, tobe formed therein. In an embodiment, the connection blocks 20 comprisesilicon, silicon dioxide, glass, and/or the like.

Over the die 12, molding compound 14, and the connection blocks 20 maybe a second interconnect layer 13. The second interconnect layer 13 maycomprise one or more layers of dielectric material 18 with conductivefeatures (illustrated as conductive features 9) formed therein. In anembodiment, the layers of dielectric material 18 are formed of aphoto-sensitive material such as polybenzoxazole (PBO), polyimide (PI),benzocyclobutene (BCB), or the like, which may be easily patterned usinga lithography mask similar to a photo resist. In alternativeembodiments, the layers of dielectric material 18 may be formed of anitride such as silicon nitride, an oxide such as silicon oxide,phosphosilicate glass (PSG), borosilicate glass (BSG), boron-dopedphosphosilicate glass (BPSG), or the like. In an alternative embodimentthe second interconnect layer 13 may comprise an interposer or packagingsubstrate, such as a silicon interposer, organic substrate, a laminatesubstrate (e.g., a 1-2-1 laminate substrate), or the like. Additionally,the second interconnect layer 13 may include a set of second externalcontacts 7 (provided through conductive features 9) for connection toanother device, such as a die, a stack of dies, a package, aninterposer, and/or the like. The another device may connect via solderbumps/balls, wire bonding, or the like through the second externalcontacts 7.

As illustrated in FIG. 1a , and discussed in greater detail below,electrical components may be electrically coupled to the upper surfaceof the second interconnect layer 13. The second interconnect layer 13(via the conductive features 9), which may act as a RDL, provideselectrical connections between those electrical components and theTVs/IPDs positioned within the connection blocks 20. The firstinterconnect layer 11 in turn provides an electrical connection betweenthe connection blocks 20 and the die 12 and/or the first set of externalcontact pads 17, as well as providing an electrical connection betweenthe die 12 and the first set of external contact pads 17. Solder balls19, which may be part of, for example, a ball grid array (BGA), may beattached to another substrate, such as a wafer, packaging substrate,PCB, die, or the like.

Embodiments such as that illustrated in FIG. 1a comprise connectionblocks 20 that may allow structures such as the through vias and IPDs tobe formed in a different type of material than the molding compound 14,thereby providing different performance characteristics. The connectionblocks 20 may comprise one or more TVs, e.g., through-silicon vias(TSVs), connecting the second interconnect layer 13 to the firstinterconnect layer 11. In addition, the connection blocks 20 maycomprise one or more integrated passive devices (IPDs), such asintegrated capacitors, integrated resistors, or the like. In the case ofthe TVs and the IPDs, the use of a silicon block allows the vias anddevices to be placed closer together. That is to say, the fineness ofthe pitch of the TVs and the IPDs is increased, allowing greater densityof via and passive device integration. In another embodiment the block20 may comprise silicon dioxide (SiO₂) which provides similarimprovements to that of silicon. For example, by using silicon orsilicon oxide a pitch of the TVs may be reduced down to about 60 μm froma pitch through molding compound which would be greater than 100 μm.

FIG. 1B illustrates a plan view of the embodiment illustrated in FIG. 1a. As illustrated, a single die 12 is located between two connectionblocks 20. Additionally, the molding compound 14 surrounds the singledie 12 and the two connection blocks 20, thereby separating the die 12from the two connection blocks 20. In such a layout the two connectionblocks 20 provide additional support and routing options to the die 12through the molding compound 14, thereby allowing more flexibility.

FIG. 1C illustrates a plan view of another embodiment in which a singledie 12 is utilized along with a single connection block 20. In thisembodiment the die 12 and the connection block 20 are aligned with eachother side by side, with the connection block 20 aligned along a singleside of the die 12. Additionally, in other embodiments the connectionblocks 20 may form a ring (either continuous or broken) around the die12. Any suitable arrangement of the die 12 and the one or moreconnection blocks 20 may alternatively be utilized.

FIG. 2a depicts an embodiment of the connection block 20. The connectionblock 20 comprises a structural material 21, such as silicon, silicondioxide (SiO₂), or the like. Holes in the structural material 21 formone or more TVs 24 and one or more integrated passive devices (IPDs) 22,such as a trench capacitor as illustrated in FIG. 2. The TVs 24 arefilled with a conductive material 25, such as a metal, to providecontacts from a first side of the block 20 to a second side of the block20. In an embodiment in which the IPD 22 comprises a capacitor or aresistor, the IPD 22 may be lined separately with conductive material 25and filled with a filler material 23. The filler material 23 compriseseither a dielectric to form an integrated capacitor or a resistivematerial to form an integrated resistor. The TVs 24 and the IPDs 22 mayinclude other components, such as adhesion layers, barrier layers, orthe like, and may include multiple layers.

FIGS. 2b-2c illustrate that, in another embodiment the IPD 22 comprisesan inductor 29. FIG. 2b illustrates one embodiment in which the inductor29 is formed in a metallization layer 27 on a single side of theconnection block 20. The metallization layer 27 may be formed on theconnection block 20 either facing the first interconnect layer 11 orfacing away from the first interconnect layer 11. The inductor 29 may beformed within the first metallization layer 27 using suitablephotolithographic, deposition, and polishing processes such as damasceneprocesses.

FIG. 2c illustrates an alternative embodiment in which, rather thanbeing formed in a single metallization layer 27 on one side of theconnection block 20, the inductor 29 may be formed through theconnection block 20. For example, TVs may be formed within theconnection block 20 in order to provide vertical sections of theinductor 29, while the vertical sections of the inductor 29 may beconnected with each other by forming connections in the metallizationlayers 27 located on both sides of the connection block 20.

In an embodiment in which the connection blocks 20 are formed ofsilicon, any suitable semiconductor processing techniques may be used toform the connection blocks 20. For example, photolithography techniquesmay be utilized to form and pattern a mask to etch vias and trenches inthe silicon in accordance with a desired pattern. The trenches may befilled with the appropriate conductive, dielectric, and/or resistivematerials using suitable techniques, including chemical vapordeposition, atomic layer deposition, electro-plating, and/or the like.Thinning techniques may be utilized to perform wafer thinning to exposethe TVs along a backside. Thereafter, a singulation process may beperformed to form the connection blocks 20 as illustrated in FIG. 2. Theconnection blocks 20 may be of any shape, such as square, rectangular,the like. Additionally, one or more connection blocks 20 may beutilized. For example, in an embodiment, a single connection block 20 isutilized, whereas in other embodiments, multiple connection blocks 20may be utilized. The connection blocks 20 may extend alongside one ormore sides of the die 12, and may form a ring (continuous or broken)around the die 12.

FIG. 3 depicts an embodiment of a package on package (PoP) device 30. Aswill be more fully explained below, the PoP device 30 provides aninnovative package-on-package structure with integrated, or built-in,passive devices incorporated into the connection blocks 20. As such, thePoP device 30 offers improved electrical performance and a higheroperation frequency relative to a standard PoP device. Additionally, thedecreased pitch of the TVs and the IPDs in the block 20 allow increasedintegration density. As shown in FIG. 3, the PoP device 30 generallyincludes a second package 32 coupled to the first package 10 throughsolder balls 36 connected to solder ball lands 37 in, for example, a BGAarrangement. However, the first and second package can be connectedthrough other means such as via solder bumps, wire bonding, or the like.

In an embodiment, the second package 32 includes several stacked memorychips 31. The memory chips 31 may be electrically coupled to each otherthrough, for example, through vias, wire bonds, or the like, representedin FIG. 2 by reference numeral 35. While several memory chips 31 aredepicted in FIG. 3, in an embodiment the second package 32 may include asingle memory chip 31. The second package 32 may also incorporate otherchips, dies, packages, or electronic circuitry depending on the intendeduse or performance needs of the PoP device 30.

As described above, in the embodiment depicted in FIG. 1a and FIG. 3 thefirst interconnect layer 11 comprises at least one layer of dielectricmaterial 16. In an alternative embodiment the first interconnect layer11 may be replaced by a suitable semiconductor material such as silicon.If silicon is used as a substrate in place of the dielectric material16, a passivation layer and a molding layer may be included between thesilicon and the solder balls 19 of the BGA. These additional layers maybe omitted when, e.g., the interconnect layer is formed from adielectric material 16.

The first package 10 also includes a molding compound 14 encasing thedie 12 and the connection blocks 20. The molding compound 14 may beformed from a variety of suitable molding compounds. As depicted in FIG.2, the connection block 20 provides the IPDs as well as the TVs for theinterconnection between the first package 10 and the second package 32.As noted above, the solder bump lands 37 are employed to mount thesecond package 32 and provide electrical connection through theconductive features 9, embedded or supported by the second interconnectlayer 13, to the TVs or IPDs in the connection block 20 that is encasedin the molding compound 14.

FIGS. 4a-4j depict various intermediate stages in a method for formingan embodiment. Referring first to FIG. 4a , a first carrier 41, e.g., aglass carrier, with a release film coating 46 formed thereon is shown.In FIG. 4b , connection blocks 20 and a die 12 are attached to the firstcarrier 41 on surface with the release film coating 46. The release filmcoating 46 may comprise an adhesive film ultra-violet (UV) glue, or maybe formed of other known adhesive materials. In an embodiment, therelease film coating 46 is dispensed in a liquid form onto the firstcarrier 41. In alternative embodiments, the release film coating 46 ispre-attached onto the back surfaces of die 12 and the connection blocks20, which are then attached to the first carrier 41.

As illustrated in FIG. 4b , the connection blocks 20 may be formedseparately and placed on the first carrier 41. In this embodiment, theconnection blocks 20 may be formed from a wafer, e.g., a silicon wafer,using any suitable semiconductor processing techniques, such asphotolithography, deposition, etching, grinding, polishing, and/or thelike, to form the through vias, IPDs, and/or the like for a particularapplication. The connection blocks may be separated from the wafer andplaced as, for example, shown in FIG. 4 b.

FIG. 4c illustrates the molding compound 14 disposed encasing the die 12and the connection blocks 20. In an embodiment, the molding compound 14comprises a molding compound formed on the structures shown throughcompression molding, for example. In another embodiment, apolymer-comprising material, such as a photo-sensitive material such asPBO, polyimide, BCB, or the like, may be used. The molding compound 14may be applied in a liquid form, which is dispensed and then cured. Atop surface of the molding compound 14 is higher than the top surfacesof the die 12 and the connection blocks 20.

Shown in FIG. 4d , a wafer thinning process comprising a grinding and/orpolishing is performed to planarize the top surface. The thinningprocess reduces and may substantially eliminate any unevenness in thetop surface. The molding compound 14 comprising portions covering topsurfaces of die 12 and connection blocks 20 is removed by the thinning,thereby exposing the TVs and/or the IPDs formed within the connectionblocks 20.

In FIG. 4e , the first interconnect layer 11 is formed over moldingcompound 14, connection blocks 20, and die 12. In an embodiment thefirst interconnect layer 11 comprises alternating layers of dielectricmaterial 16 with layers of conductive features 15 to comprise a RDL. Thebottom surface of the first interconnect layer 11 may be in contact withthe top surface of the die 12, the connection blocks 20, and the moldingcompound 14. The dielectric material 16 may comprise many differenttypes of materials as described earlier in reference to FIG. 1a . Theconductive features 15 comprising a RDL may include lower portions whosebottoms are electrically coupled to the through vias 24 and IPDs 22 inthe connection blocks 20 as shown in FIG. 2. The RDL with conductivefeatures 15 may also include top regions with external contact pads 17.

In accordance with some embodiments, the formation of the firstinterconnect layer 11 may include forming a dielectric material, etchingand removing portions of the dielectric material, forming anunder-bump-metallurgy (UBM, not shown) over the dielectric material,forming and patterning a photo resist (not shown) to cover portions ofthe UBM, and plating a metallic material to form the first set ofexternal contact pads 17. The exposed portions of the UBM are thenremoved. The first set of external contact pads 17 may be formed ofcopper, aluminum, tungsten, or the like.

FIG. 4f shows a second carrier 42 with a release film coating 46attached to the top side of the first interconnect layer 11. The releasefilm coating 46 of the second carrier 42 may be similar to the releasefilm coating 46 of the first carrier 41. The wafer is then flipped over.

In FIG. 4g , the first carrier 41 is de-bonded, for example, by exposingrelease film coating 46 to a UV light, causing it to lose its adhesiveproperty. The release film coating 46 is also removed. An optionalbackside thinning process may be performed to thin and planarize thesurface of the wafer, possibly to expose through vias formed in the die12.

FIG. 4h depicts the second interconnect layer 13 formed over the die 12and connection blocks 20. The second interconnect layer 13 may beconstructed of dielectric materials 18 similar to dielectric materials16 as described in reference to FIG. 1a . The second interconnect layer13 may be formed in a way similar to the first interconnect layer 11.The second interconnect layer 13, in an embodiment a RDL, providesinterconnections between the TVs in the connection blocks 20 and theexternal contacts 7.

FIG. 4i depicts a third carrier 43 attached to the backside of thewafer. The second carrier 42 is removed in a fashion similar to thefirst carrier 41. Solder balls 19 may be placed along the top side ofthe wafer forming a BGA in contact with the first set of externalcontact pads 17 as shown in FIG. 1 a.

Finally, FIG. 4j depicts removal of the third carrier 43 in a fashionsimilar to the first and second carriers 41/42. Optionally, dicing tape44 is then adhered to a surface of the second interconnect layer 13. Insome embodiments, multiple PoPs may be formed simultaneously. In theseembodiments, dicing tape 44 may be applied and a dicing processperformed along lines 45 to separate a structure into a plurality ofpackages, such as that illustrated in FIG. 1a . In an embodiment each ofthe resulting structures include a die 12 and connection blocks 20encased laterally in molding compound 14. The resulting packages maythen be bonded to other packaging components such as package substratesor a PCB through solder balls 19 or through additional solderballs/bumps attached to the opposite side of the die with second set ofexternal contacts 7, such as illustrated in FIG. 3.

In an embodiment, a semiconductor device having a die, a first material,and a second material is provided. The second material and the firstmaterial are positioned along a major axis of the die. The firstmaterial comprises one or more conductive features extending through thefirst material.

In another embodiment, a semiconductor device comprising a top packageand a bottom package is provided. The bottom package comprises a die anda connection block separated from the die by a molding compound.

In yet another embodiment, a method of forming a semiconductor device isprovided. The method comprises providing a die and a connection blockhaving one or more conductive elements. A layer comprising the die andthe connection block separated by a material layer, wherein theconnection block is formed of a material different from the materiallayer, is formed.

Although the present embodiments and their advantages have beendescribed in detail, it should be understood that various changes,substitutions and alterations can be made herein without departing fromthe spirit and scope of the disclosure as defined by the appendedclaims.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed, that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the present disclosure.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps.

What is claimed is:
 1. A semiconductor device comprising: a top package;and a bottom package operably coupled to the top package, the bottompackage comprising a die and a connection block separated from the dieby a molding compound, wherein the connection block comprises aplurality of through vias and an integrated passive device, theintegrated passive device comprising a surface planar with the die, theconnection block, and the molding compound.
 2. The semiconductor deviceof claim 1, wherein the connection block comprises silicon.
 3. Thesemiconductor device of claim 1, wherein the connection block comprisessilicon dioxide.
 4. The semiconductor device of claim 1, wherein theplurality of through vias has a pitch of about 60 μm.
 5. Thesemiconductor device of claim 1, wherein the integrated passive deviceis a trench capacitor.
 6. The semiconductor device of claim 1, furthercomprising a redistribution layer in an electrical connection with boththe die and the connection block.
 7. The semiconductor device of claim1, wherein the bottom package further comprises a second connectionblock separated from the die and the connection block by the moldingcompound.
 8. A semiconductor device comprising: an integrated passivedevice with a planar surface, the integrated passive device beinglocated within a first material; a through via extending from a firstside of the first material to a second side of the first material; a dieseparated from the first material by a first space; an encapsulantfilling the first space, wherein the encapsulant, the die, and theintegrated passive device are planar with each other at the planarsurface; a redistribution layer extending over the first material, theencapsulant, and the die; and a memory chip electrically connected tothe redistribution layer.
 9. The semiconductor device of claim 8,wherein the integrated passive device is a capacitor.
 10. Thesemiconductor device of claim 9, wherein the capacitor is a trenchcapacitor.
 11. The semiconductor device of claim 8, wherein the firstmaterial is silicon dioxide.
 12. The semiconductor device of claim 8,wherein the first material is silicon.
 13. The semiconductor device ofclaim 8, further comprising a second through via extending from thefirst side of the first material to the second side of the firstmaterial, wherein a pitch between the through via and the second throughvia is about 60 μm.
 14. The semiconductor device of claim 8, furthercomprising an external connection in contact with the redistributionlayer.
 15. A semiconductor device comprising: a stack of memory deviceselectrically connected to each other; and a package electricallyconnected to the stack of memory devices, the package comprising: asemiconductor die; an molding compound laterally encapsulating thesemiconductor die; a connection block extending through the moldingcompound, wherein the molding compound is located between thesemiconductor die and the connection block; an integrated passive devicelocated within the connection block, wherein the integrated passivedevice, the molding compound, and the semiconductor die are planar witheach other at respective first sides; and through vias extending fromthe first side of the connection block to a second side of theconnection block.
 16. The semiconductor device of claim 15, wherein theconnection block comprises silicon.
 17. The semiconductor device ofclaim 15, wherein the connection block comprises silicon dioxide. 18.The semiconductor device of claim 15, wherein a pitch of the throughvias is about 60 μm.
 19. The semiconductor device of claim 15, whereinthe integrated passive device is a trench capacitor.
 20. Thesemiconductor device of claim 15, further comprising a redistributionlayer overlying the molding compound, the semiconductor die, theconnection block, and a second connection block.